Process of internally tinning metal vessels.



F. VAN DER VELDEN. PROCESS OF INTERNALLY TINNING METAL VESSELS.

APPLIUATION FILED AUG.17, 1911,

Patented Sept. 2, 1913.

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Inventor Friedrich van der Velden Wit n e,s,s es

y haw uumd Attorney UNITED srra'ras PATENT orrion.

FRIEDRICH VAN DER .VELDEN, 0F BARMEN, GERMANY, ASSIGNOR-TO WICKUELER KUEP- PER BRAUEREI AOTIENGESELLSCHAFT, OF E BEBFELD, GERMANY, A CORPORA- TION OF GERMANY.

PROCESS OF INTER/RALLY TINNING METAL VESSELS.

To all whom 1' t may concern:

- Be it known that I, FRIEDRICH VAN DER Venous. a subject of the German Emperor and residing at Barmen, Germany, have invented a certain new and useful Improved Process of Internally Tinning Metal Vessels,

of which the following is a specification.

The subject-matter of this invention is a process of internally tinning metal vessels, particularly metal casks or barrels.

Metal vessels particularly iron casks or barrels, have been tinned heretofore by completely immersing the previously cleansed vessel in a tin bath.

The improved process according to this invention is distinguished from this known process by the tin being introduced in a solid or liquid form into the interior of the vessel, as in the process already known for enanieling articles, and by the outside of the vessel being then heated. In the present instance, the latter operation is performed by immersing the vessel in a bath having a higher temperature than the melting point of tin which is about 228 C. By rolling the vessel or placing the same into the requisite positions, the mass of tin in the vessel is uniformly distributed therein. This bath havin a high temperature which is for acting independently of the inner tin coating of the vessel on the outside of the same, is preferably formed by employing a material whiclriu itself is suitable for treating the outside of the cask. Therefore, either lead which melts at about 326 C. or zinc whose meltingpoint is about 420 C. will be preferred. When one of these two substances is employed the outside of the vessel is conse-- quently simultaneously coated with lead or zinc.

As zinc and lead are respectively seven and ten times cheaper than tin, coating the outside of the vessel with zinc or lead simultaneously as the inside is coated with tin has the adyal'itage of materially lessening the cost as compared with processes known heretofore in which, When the inside was tinned, the outside had also to be tinned. In addition, zinc and lead are materially more resistirg to the formation of rust.

It is well-known in itself to provide hollow bodies simultaneously Within and" without with a metal coating.

The new process is particularly adapted Specification of Letters Patent.

Application filed August 17, 1911.

Patented Sept. 2, 1913.

Serial No. 644,588.

for internally tinning iron beer casks or barrels particularly for pasteurizing and conveying purposes.

The separate operations of the process are shown for the sake of example in the accompanying drawing, in which Figure 1 is a perspective view of a furnace adapted to carry out the process with the cask to be tinned. Figs. 2 to 6 show the separate steps of the operation in section.

The cask first undergoes preliminary treatment, being carefully cleansed inside and out andwashed out with hot water. Then after say J; to liter, of chlorate of zinc is inserted and after the tin has been introduced in liquid or solid form. the cask (1, as may be seen from Fig. 1, is raised upon the furnace (Z by means of a hoisting device (2 attached to the roof 7), and is set into the depression (1 of the furnace, in which depression is found the exterior bath, for instance a lead bath, brought. to the proper temperature by the fire (P. In this position the tinning of the bottom takes place. The opening through which the chlorate of zinc and tin are introduced is, as may be seen better from Fig. 9., at this time left open, so that the vapor formed by the chlorate of zinc can escape. The cask is then turned over for the purpose of tinning the walls (Fig. 2). By means of tongs the operator gives the cask a rotating movement whereby the liquid tin (2 found within and simultaneously the liquid lead, or the like, 7 found in the depression of the furnace are successively brought into contact with all points of the wall.

Fig. 3 illustrates how the interior of the cask is lighted by means of an introduced lamp h, in order to determine whether there are faulty places within, that is to say, places where no tin coating has formed. If such places i are discovered the cask is-put in an inclined position as may be seen from Fig. 4; simultaneously these places are finished by means of a rod in on the end of which is a little brush k. This treatment is continued until a complete coating has formed. Tlereupon follows the tinning of the top in the manner shown in Fig. 5. The cask is tipped over after the opening a has been closed by a screw cap a Then after all the inner and outer surfaces have been successively treated the cask is raised from the flowed; the existin furnace, the screw cap removed and, Fig. 6' shows, any superfluous tin left within is emptied into a pan Z.

The trials made with the improved tinning process according to the invention have shown that the tin coating is so perfeet and durable that subsequent tinning, such as was frequently necessary after the casks had been used once in the case of the customary process known heretofore, can be saved during the entire life of the cask.

In this improved process the tin is a tin liquid, penetrates wellinto' any pores and recesses in the iron and can be applied to the walls everywhere more uniformly and in a thin but perfectly suflicient layer.

Places in the surface of the iron contain ing rust or other impurities are at once recognizable when an electric incandescent lamp, for example, is introduced into the cask. In consequence of the heat continuously acting from without on the iron wall the tin does not adhereeto such impure places before the impurity is removed, which can be done without special difliculty from without with suitable tools through the opening of the cask.

When casks are tinned in the tin bath in the manner known heretofore, on the contrary, such places are generally overrusty places spread, particularly when the thin covering of tin is pressed in, e. g. during pasteurization, in

consequence of the high internal pressure. In this manner, on the one hand the iron wall is soon corroded through by the rust in said bath, whereby the outside is covered with a layer of the metal of the bath and the inside simultaneously covered with a thin layer of the other metal.

2. The herein described rocess of simultaneously coating the insi e and outside of vessels with different metals, said process consisting in placing tin in the vessel to be coated; floating the vessel in a bath of molten metal having a higher'melting point than tin; and turning the vessel from side to side and end to end in said bath, whereby the inside is covered with a thin layer of tin and the outside simultaneously covered with a layer of the metal of the bath.

In testimony whereof, I affix my signa ture in the presence of two witnesses.

FRIEDRICH VAN DER VELDEN. [L. s.] Witnesses:

ALBERT F. NUFER, WILHELM SUMMER. 

